Make time run super-slow. Six ND filters tested
Fast shutter speeds are great for freezing motion, but that’s not always what you want when you’re taking a photograph. Mount your camera on a tripod and set a long exposure, and you can add motion blur to subjects like weirs and waterfalls, for a much more dreamy look. Tripods also make it possible to blur people and vehicles out of busy street scenes as they’re walking around, for cleaner architectural shots. The only problem is enabling a long exposure in bright light, such as on a very sunny day, as over-exposed and even blown-out photos are likely.
One solution is to fit a high-density neutral filter to your lens, typically one with a rating of 10 stops. These dark filters reduce the amount of light passing through the lens. If, for example, a sunny scene would require a setting of f/11 at 1/125 sec for a correct exposure, fitting a 10-stop ND filter will enable you to slow the shutter speed to eight full seconds at f/11. Another option, which is also particularly advantageous when shooting video, is to use a variable or ‘fader’ ND filter. Based on two polarising filters, one of which is rotated against the other, these usually give a range of between two and eight stops.